JP7069219B2 - Composite form in wound healing - Google Patents

Description

The present invention relates to composite foam materials specifically used in wound healing and methods of producing composite materials.

Wound dressings are used to heal and protect wounds. The ability of the wound dressing to absorb and retain exudate from the wound is very important for the healing process. The liquid handling capacity of the dressing also affects the frequency of dressing changes, which should be minimized to promote wound healing. In various applications, hydrophilic materials are used in wound dressings, especially in hydrophilic foams (such as hydrophilic open-cell urethane foams), to absorb and retain wound fluid.

To optimize this liquid handling capacity, the wound pad in the wound dressing can preferably include a multi-layer design, where each layer is preferably a different material (especially a different foam material) and therefore different capacities and. Has functionality. To the extent such a multi-layer design is known in the art, the layers are laminated by means of an adhesive and / or by mechanical lamination. This stacking is associated with multiple shortcomings. In particular, the absorbent (eg hydrophilic foam) swells during use and thus swells when absorbing liquid, thus exerting pressure on the bonds between the layers and / or increasing the thickness, which causes deformation of the dressing (eg, eg). Can result in curling or cupping) and delamination of layers.

US Pat. As provided on the absorption core layer. Similarly, Patent Document 2 relates specifically to a multi-layer wound dressing comprising a non-woven layer sandwiched between two foam layers, all layers being bonded together using a heat-activated binding web.

Combining two urethane foams to result in a composite material (in principle, for example from a bicolor foam) or to produce a composite material with parts with different physical properties (eg, different compressive strengths). Is known. Typically, the two foams are prepared separately using different processing methods.

Patent Document 3 discloses a composite form including a first form and a second form, the forms being at least partially directly connected. The composite foam of Patent Document 3 is prepared by casting an aqueous emulsion onto the previously prepared first foam (to obtain a second foam) and is cured as it is. However, when using the first foam as the cast substrate, it is typically difficult to control the final thickness of the second foam. As taught in Patent Document 3, casting an emulsion containing more than 40% water by weight onto a foam substrate can result in rapid absorption of water from the emulsion or the surface of the foam layer substrate. It results in either absorption of the entire emulsion into the bubbles (especially due to gravity). When cured, both phenomena result in a wide interface region (> 500 μm) that impedes fluid transfer between foams. In addition, this laminate exhibits severe strain from puckering resulting from water absorption into the foam layer substrate.

Thus, foam composites with different areas of functionality (especially layers) that maintain their functionality during use (especially during use as medical dressings), with particularly different functionality 2 There is a need in the art to provide foam composites that avoid or minimize at least one of the disadvantages described above with respect to poor fluid migration across the interface between two foam layers.

US7,759,537 EP2659865 WO2013 / 00910

According to the first aspect of the present invention, these and other purposes are
A first foam layer, comprising a first hydrophilic polyurethane foam material.
A second foam layer, comprising a second hydrophilic polyurethane foam material.
Achieved by composite materials, including
The fluid holding capacity of the second foam layer is 20% or more, preferably 25% or more larger than the fluid holding capacity of the first foam layer, and the fluid holding capacity is the highest according to EN13726-1: 2002. It is defined as the ability to retain solution A when a large amount of solution A is first absorbed and exposed to a pressure of 40 mmHg for 2 minutes.

Partly, the present invention is a composite material comprising at least two different hydrophilic polyurethane foam materials, which are realized as layers, they have different fluid absorbency and / or retention capacity, but overall fluid control. Based on the realization that it allows for increased flexibility in relation to.

According to the present invention, the term "hydrophilic" refers to A. D. McNaught and A.M. IUPAC: Compendium of Chemical Terminology, compiled by Wilkinson, 2nd Edition ("Gold Book"), Blackwell Scientific Publications, Oxford (1997), as defined in Oxford (1997), ISBN 0-9. Generally refers to the ability of a molecular entity or substituent to interact with a solvent (especially water or other polar groups).

With respect to materials, the term "hydrophilic" generally refers to the water permeation properties of a material or the water-attracting properties of a material. In the context of a material with pores (eg, open cell foam, etc.) or a material with through holes, typically if the material sucks up water, such material is determined to be "hydrophilic".

In the claims, the terms "comprising" and "complyse (s)" do not exclude other elements or steps, and the indefinite article "one (a)" or "one (an)". ) ”Does not exclude multiple elements or steps. For example, the hydrophilic polyurethane foam material constituting the foam layer and comprising the first hydrophilic polymer may be an additional polymer (s), in particular another polyurethane polymer and / or another (additional) polymer that is not a polyurethane polymer. May include. Similarly, as a further example, more than two layers, especially two or more foam layers, may be present in the composite.

The mere fact that certain means are listed in different dependent claims does not indicate that the combination of these means cannot be used in an advantageous manner.

According to the present invention, the term "composite material" refers to A.I. D. McNaught and A.M. IUPAC: Compendium of Chemical Terminology, compiled by Wilkinson, 2nd Edition ("Gold Book"), Blackwell Scientific Publications, Oxford (1997), as defined in Oxford (1997), ISBN 0-9. Generally refers to a multi-component material containing different (non-gas) phase domains (at least one type of phase domain is a continuous phase, preferably both phase domains are continuous phases).

It should be understood that a "layer" as used in accordance with the present invention has continuous expansion in one plane (x and y directions) and a thickness perpendicular to the plane (z direction).

According to the present invention, "fluid retention capacity" is defined as the ability to retain solution A when the maximum amount of solution A is first absorbed and exposed to a pressure of 40 mmHg for 2 minutes according to EN 13726-1: 2002. To. Fluid retention capacity is expressed herein in units of mass (kg) of retained solution A per volume (m ³ ) of foam material.

Solution A (as defined in EN13726-1) consists of a solution of sodium chloride and calcium chloride containing 142 mmol of sodium ion and 2.5 mmol of calcium ion as chloride salt. This solution has an ionic composition equivalent to human serum or wound exudate. The solution is prepared by dissolving 8.298 g of sodium chloride and 0.368 g of calcium chloride dihydrate in deionized water up to the "1 L" marking in a volumetric flask.

In a plurality of embodiments of the present invention, the thickness of the first foam layer is smaller than the thickness of the second foam layer, preferably the thickness of the first layer is less than 40% of the total thickness of the composite material. This facilitates rapid transport through the first foam layer to the second foam layer.

Preferably, the composite is included in a medical dressing (eg, wound dressing), the first foam layer is adapted to function as a wound contact layer and / or a wound fluid trapping layer, and the second foam layer is a wound. It can be adapted to function as a fluid holding layer. In such a dressing configuration, it is advantageous that the fluid is rapidly absorbed into the first foam layer and subsequently transported into the second foam layer. By adapting the thickness of the first foam layer to less than the thickness of the second layer, the transport of wound fluid through the first foam layer to the second foam layer can be optimized.

In a plurality of embodiments of the present invention, the first foam layer has a thickness of 0.5 mm to 2.5 mm, preferably 1.0 mm to 2.0 mm (1.5 mm, etc.).

In a plurality of embodiments of the present invention, the second foam layer has a thickness of 1.5 mm to 7.0 mm, preferably 2.0 mm to 5.0 mm (3.5 mm, etc.).

In a plurality of embodiments of the present invention, the combined thickness of the first foam layer and the second foam layer is 3 to 8 mm, preferably 3 to 6 mm (5 mm, etc.).

In a plurality of embodiments of the invention, the first foam layer has a free swelling absorption capacity (maximum) of 500-1200 kg / m ³ , preferably 600-1000 kg / m ³ , as measured by EN13726-1: 2002. Corresponds to absorption capacity).

In a plurality of embodiments of the invention, the second foam layer is characterized by a free swelling absorption capacity (corresponding to maximum absorption capacity) of 800-2500 kg / m ³ as measured by EN13726-1: 2002. Be done.

In a plurality of embodiments of the present invention, the second foam layer has a fluid holding capacity of 800 kg / m ³ or more, preferably 900 kg / m ³ or more, more preferably 1000 kg / m ³ or more.

In a plurality of embodiments of the present invention, the second foam layer has a fluid holding capacity corresponding to 80% or more, preferably 85% or more of its free swelling absorption capacity.

In a plurality of embodiments of the present invention, the fluid holding capacity of the second foam layer is 30% or more, preferably 40% or more larger than the fluid holding capacity of the first foam layer. In a plurality of embodiments of the present invention, the fluid holding capacity of the second foam layer is 50% or more, preferably 100% or more, and more preferably 150% or more larger than the fluid holding capacity of the first foam layer. ..

In a plurality of embodiments of the present invention, the first foam layer has a fluid retention capacity corresponding to less than 80% of its free swelling absorption capacity.

In a plurality of embodiments of the present invention, the first foam layer has an absorption rate of 10 μL / sec or higher, preferably 20 μL / sec or higher or 30 μL / sec or higher. For example, the first foam layer has an absorption rate of 10-40 μL / sec.

In a plurality of embodiments of the present invention, the second foam layer has an absorption rate of 1 μL / sec or higher, preferably 3 μL / sec or higher or 5 μL / sec or higher. For example, the second foam layer has an absorption rate of 1 to 20 μL / sec (2 to 15 μL / sec, etc.).

According to the present invention, the term "absorption rate" is given of a fluid as measured according to TAPPI standard T558 OM-97, using 30 μL of solution A according to EN1372-1: 2002 as the test solution. It is defined as the rate of absorption of volume (volume / time).

In a plurality of embodiments of the present invention, the first foam layer has an absorption rate 100% or more, preferably 200% or more, more preferably 300% or more higher than the absorption rate of the second foam layer. For example, in a plurality of embodiments of the present invention, the absorption rate is 400% or more, preferably 500% or more or 600% or more higher than the absorption rate of the second foam layer.

In a plurality of embodiments of the present invention, at least one of the first and second foam layers comprising the first and second hydrophilic polyurethane foam materials, respectively, leads to a prepolymer (hydrophilic urethane foam layer). ) Is obtained or obtained by a process containing less than 40% water, preferably less than 30% water.

For example, in a plurality of embodiments of the present invention, the water content of the aqueous mixture is 10 to 30% w / w (10 to 25% w / w, etc.).

In a plurality of embodiments of the invention, the first and second hydrophilic polyurethane foam materials are open cell porous hydrophilic with a density of 60-180 kg / m ³ as measured according to standard method ISO845: 2006. Selected from the form.

As used herein, the term "open cell" refers to the pore structure of foam, where the pores in the pore structure are connected to each other and interconnected with a path for fluid flow through the foam material. Form a network.

In a plurality of embodiments of the present invention, the first hydrophilic polyurethane foam material and the second hydrophilic polyurethane foam material have a porosity of 70% or more, preferably 80% or more, and the pores are essentially open cells. The pore structure is presented.

Complexes according to the invention can be used particularly advantageously in wound healing to absorb and retain fluid from the wound site (eg, wound exudate). The first foam layer, which comprises the first hydrophilic polyurethane foam material, which is typically placed in contact with the wound site, absorbs or absorbs the wound exudate into the composite material relatively rapidly. The second foam layer, which is advantageously adapted to have fluid-assisting absorption properties and contains a second hydrophilic polyurethane foam material (and is typically placed further away from the wound), is relatively It has a high fluid (eg, wound exudate) retention capacity and, as a result, can be advantageously adapted so that the wound exudate is retained therein.

According to the invention, the term "wound site" or "wound" includes any open or closed wound, such as inertial wounds, acute wounds and postoperative wounds (eg, closed incisions and scar treatment, etc.). Is understood as (but not limited to).

Thus, in one embodiment, when the composite is used in wound healing, the first foam layer facilitates such absorption and / or transfer of wound exudate from the wound site to the second foam layer. Can be advantageously adapted to contact the wound site.

According to the second aspect of the present invention, the composite material is
A first comprising a first hydrophilic polyurethane foam material, the first foam layer having a first side fitted to face the application area, preferably facing the wound area during use. Foam layer and
A second foam layer, comprising a second hydrophilic polyurethane foam material,
Including
The plurality of channels extend from the first side of the first foam layer through the entire first foam layer into at least a part of the second foam layer, and the channels are 0.1 mm to 4.0 mm. It has an average diameter of preferably 0.5 mm to 3.0 mm, more preferably 1.5 mm to 2.5 mm.

A plurality of channels provided in the first foam layer and extending into at least a portion of the second foam layer, in addition to the initial absorption of the fluid (eg, wound exudate, etc.), the first foam layer. Promotes both transport of fluid across the interface between the first foam layer and the second foam layer through, and as a result, from the first side of the foam layer into the second foam layer. The overall transport of the fluid is improved.

In a plurality of embodiments of the invention, the first side of the first foam layer is at least partially coated with an adhesive (eg, a silicone-based adhesive) and the plurality of channels are the first foam layer. It extends through the whole and further into at least part of the second foam layer. The adhesive coating, which can function to adhere the first side of the first foam layer to the wound site, is at least some of the continuous foam holes present on the first side of the first foam layer. It can reduce the ability of the first foam layer to absorb fluid. However, by providing the plurality of channels in the first foam layer, the absorption capacity is maintained or optionally improved in the presence of the adhesive coating. Multiple channels may be provided before or after the first side is coated with the adhesive, preferably before the first side is coated with the adhesive. Multiple channels may be particularly useful for improving the absorption of thick wound exudate.

According to the second aspect, the term "channel" generally allows a continuous structure (ie, direct flow of fluid (liquid or gas), unless filled with fluid during intended use. , Which is understood to refer to a structure that is not blocked by the material constituting the layer (particularly the hydrophilic polyurethane foam material). In multiple embodiments, these channels are essentially "continuous" over their entire length in the above sense.

In particular, these channels can be filled with fluid during intended use, while during use (eg during use in the presence of material whose density can increase during use due to swelling). , In the sense that they are not permanently closed to the liquid flow), these channels maintain a continuous structure.

The (average) diameter of these channels can increase during use or decrease to the extent that (more typically) essentially all channels are not closed to essentially all fluid flows. It is understood that it can be done. In a plurality of embodiments of the invention, the channels have an aspect ratio of at least 1: 1, preferably at least 2: 1, more preferably at least 5: 1, i.e. (average) continuous length vs. (average) continuous. Characterized by the ratio of diameters.

In a plurality of embodiments of the invention, the channels are arranged essentially perpendicular to the first foam layer and the second foam layer, and thus also essentially perpendicular to the interface between the two layers. be.

In a plurality of embodiments of the invention, channels are absent in more than 20%, preferably more than 30% of the total area of the first side of the first foam layer. For example, in a plurality of embodiments of the present invention, the entire area of the first side of the first foam layer comprises a first central portion and a second portion surrounding the first portion, and the channel is the first. Only present in the central portion of the, the region of the second portion is more than 20% of the total region of the first side of the first foam layer.

In a plurality of embodiments of the invention, the channels are arranged in a pattern.

In a plurality of embodiments of the invention, the channel is a continuous pattern of squares (s) on the region of the first side of the first foam layer, or the first side of the first foam layer. Form a continuous pattern of circles (s) growing from the center of the region.

In a plurality of embodiments of the invention, the channel forms a decorative or informative pattern, such as a wave or text that conveys a message.

In a plurality of embodiments of the invention, at least some of the channels have diameters that vary along their length, and / or at least one subset of the channels is another of the channels. It has a different diameter than the diameter of the subset.

In a plurality of embodiments of the invention, the area density of channels per entire area on the first side of the first foam layer ranges from 0.5 channels per square centimeter to 200 channels per square centimeter, preferably per square centimeter. From 1 channel to 100 channels per square centimeter, more preferably from 1 channel per square centimeter to 50 channels per square centimeter.

The above embodiments of the channel, alone or in combination, closely adjust the fluid-guided properties for specific situations (eg, specific fluid viscosity, specific flow rate, specific intended use, etc.). Make it possible.

In a plurality of embodiments of the invention, for example, the plurality of channels are formed by punching (eg, using rotary die cutting or needles), heating pins, and / or laser beam application.

The embodiments, features and effects described in connection with the composite material according to the first aspect (above) and the third aspect (below) of the present invention are the above-mentioned composite materials according to the second aspect of the present invention. Applicable with necessary changes.

According to the third aspect of the present invention, the objectives considered above and other objectives are:
A first foam layer, comprising a first hydrophilic polyurethane foam material.
A second foam layer, comprising a second hydrophilic polyurethane foam material.
Achieved by composite materials, including
An interfacial bond volume is present between the first foam layer and the second foam layer.
The interfacial bond volume comprises a mixture of the first foam layer and the materials constituting the second foam layer.
The thickness of the interface-bonded volume is less than 200 μm, preferably less than 100 μm, and more preferably 50 μm or less.

According to these embodiments, the composite material comprising the first foam layer is provided that is directly attached to the second foam layer (eg, by physical "sticky" interaction) and thus in direct contact. Will be done.

According to these embodiments, the need to provide an "external" binding means (eg, by means of providing an adhesive layer between the foam layers) that holds the first layer and the second layer together is avoided. To. Omitting the (separated) adhesive layer is particularly relevant for fluid transport between the foam layers, as the presence of additional binding means (such as the adhesive layer) can reduce or suppress fluid transfer between the bonded layers. It is advantageous.

In a plurality of embodiments of the present invention, the physical properties of at least one of the materials contained in the interfacial bonded volume are different from each other as compared with the materials constituting the first foam layer and the second foam layer. For example, the material in the interfacial bonded volume may have a higher density or a different foam structure (eg different pore sizes), respectively, as compared to the first foam layer and the second foam layer.

In a plurality of embodiments of the present invention, the "thickness" of the interfacial bond volume between the first foam layer and the second foam layer (ie, defined by the first foam layer and the second foam layer). The extension of the interface-bonded volume perpendicular to the xy plane) is in the range of 25 to 200 μm, preferably 25 to 100 μm.

It is advantageous to minimize the interfacial bond volume, as the absorption and / or retention capacity of the material can be reduced at the interfacial bond volume. Therefore, minimizing the interfacial bond volume (ie, its thickness) is expected to promote and improve fluid transfer between layers.

When used in accordance with the present invention, the term "interfacial bonded volume" is understood to relate to the volume in the interfacial region between the first foam layer and the second foam layer, the volume of which is the first hydrophilic. It comprises both a sex polyurethane foam material and a second hydrophilic polyurethane foam material (eg a mixture thereof), the materials of which are bonded together in the interfacial volume. The thickness of the interfacial volume refers to the thickness (or interfacial penetration depth) in the direction of the thickness of the foam layer.

The interfacial bonded volume is a separate phase within the entire composite that can be distinguished from the "pure" first foam layer and second foam layer, respectively, by light microscopy, for example. The different phases (interfacial bond volume, "pure" first foam layer, and second foam layer) are based on differences in physical properties, such as differences in density and / or differences in pore size and distribution. It can also be identified based on.

In a plurality of embodiments of the present invention, the fluid holding capacity of the second foam layer is 20% or more, preferably 25% or more larger than the fluid holding capacity of the first foam layer, and the fluid holding capacity is EN13726. -1: Defined as the ability to first absorb and retain the maximum amount of Solution A when exposed to a pressure of 40 mmHg for 2 minutes according to 2002.

In a plurality of embodiments of the present invention, the second foam layer has a fluid holding capacity of 800 kg / m ³ or more, preferably 900 kg / m ³ or more.

The embodiments, features and effects described above in connection with the composite material according to the first and second aspects of the invention make the necessary changes to the composite material according to the third aspect of the invention. In addition, it is applicable.

According to a fourth aspect of the invention, the objectives considered above and other objectives are methods of making composite materials.
(I) An aqueous mixture containing a polyurethane prepolymer is prepared and the water content of the aqueous mixture is less than 40% w / w, preferably less than 30% w / w, preferably less than the total weight of the aqueous mixture. Steps that are less than 25% w / w and
(Ii) The step of applying the aqueous mixture from step (i) onto the carrier material, and
(Iii) The top of the aqueous mixture, such as the already cured hydrophilic polyurethane foam layer cast onto the carrier material in step (ii) before the aqueous mixture is substantially completely cured. And the steps to apply,
(Iv) Allows the aqueous mixture to be cured substantially completely, thereby comprising a first foam layer comprising a first hydrophilic polyurethane foam material and a second comprising a second hydrophilic polyurethane foam material. And the steps to produce a composite material containing a foam layer of
Achieved by methods, including.

In a plurality of embodiments of the invention, the method described above further preferably comprises the step (v) of drying the composite material.

The term "curing", when used in accordance with the present invention, means the formation of (crosslinked) bonds between polymers of prepolymers in an aqueous mixture, in particular the (crosslinked) bonds are hydroxyl groups on the first polymer. A urethane bond formed through a reaction between a group and an isocyanate (NCO) group on the second polymer, or an amine group on the first polymer and an isocyanate (NCO) group on the second polymer. It is or contains a urea bond formed through a reaction between them.

In a plurality of embodiments of the invention, the degree of cure of the aqueous mixture is 50-90%, preferably 70-90% at the stage of applying the layer of the already cured hydrophilic polyurethane foam layer in step (iii). Between. By adapting the degree of cure of the aqueous mixture, sufficient bonding between the first foam layer and the second foam layer is achieved while simultaneously and advantageously minimizing the interfacial bond volume (ie its thickness). can do. The peel strength between the first foam layer and the second foam layer can therefore be adapted to exceed the (tensile) strength of the weakest foam layer, and the peel strength test is an interfacial bond volume. Will lead to destruction within one of the layers, not within.

Steps (i)-(iii) are advantageously carried out as a rapid continuous step to ensure the desired degree of cure in the aqueous mixture when an already cured foam layer is applied, thereby ensuring the desired degree of cure. Ensuring sufficient bonding (and thus in the generated interfacial bonding volume) between the foam layers.

The term "hardness", as used herein, relates to the percentage of reacted isocyanate groups as measured by Fourier Transform Infrared Spectroscopy (FTIR). In this context, 100% cure means that essentially all isocyanate (NCO) groups have reacted, while 0% cure means essentially no isocyanate (NCO) groups have reacted. Means that. The amount of NCO groups and the corresponding degree of cure at different stages of the method of producing the composite material can be monitored by FTIR. Prior to mixing the prepolymer composition with water (ie, prior to step (i)), the NCO cardinal number corresponding to 0% cure is measured. The terms "fully cured" and "completely cured" mean 90-100% cure when used in accordance with the present invention.

The present inventor applies a (already cured) foam layer to the top of a curable aqueous prepolymer mixture of other foam layers to provide a (already cured) foam layer containing a hydrophilic foam material. I was surprised to find that it can be conveniently and directly applied directly to another foam layer containing a hydrophilic foam material. Although not bound by theory, the relatively low water content in an aqueous prepolymer mixture according to the present invention is a rapid increase in the aqueous prepolymer mixture into other (already cured) foams. It is believed that absorption is avoided or minimized, which would otherwise produce an unwanted interfacial bonding volume (ie its large thickness) between the layers, and / or the two foam materials. It provides a fully integrated composite material.

In a plurality of embodiments of the present invention, step (i) of preparing an aqueous mixture containing a prepolymer comprises mixing the prepolymer with water.

In a plurality of embodiments of the invention, the water content of the aqueous mixture is less than 30% w / w (compared to the total weight of the aqueous mixture), preferably less than 25% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 5-40% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 5 to 30% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 5 to 25% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 5 to 20% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 10-40% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 10 to 30% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 10-25% w / w. In a plurality of embodiments of the present invention, the water content of the aqueous mixture is 15-20% w / w.

The water content in the aqueous mixture can be advantageously adapted such that the minimum amount of water required to produce the foam is used. Minimize the use of water in the aqueous mixture, as low amounts of water in the composite mean low shrinkage of the layers in the composite during the drying step, thus reducing stress on the bonding between the layers. That is particularly advantageous in the drying step (v) of the method. Minimizing the amount of water in the aqueous mixture is advantageous for minimizing the permeation of the aqueous mixture into the foam layer of the already cured foam, the aqueous mixture with higher viscosity. I will provide a.

In a plurality of embodiments, the thickness of the aqueous mixture as applied in step (ii) is 0.5 mm to 5 mm.

In a plurality of embodiments of the invention, the aqueous mixture further comprises at least one surfactant, preferably a nonionic surfactant.

In a plurality of embodiments of the invention, preferably the application (casting) step (ii) is carried out by the "coat hanger die" method in order to leave the upper surface of the aqueous mixture free of binding of the second foam layer. Will be carried out.

The already (fully) cured hydrophilic urethane foam is bonded to the top of the aqueous mixture in the application step (iii). The "applying" step (iii) can be implemented by any method known to those of skill in the art (eg, cast to a thickness between carriers, or cast thick and cut to size).

In a plurality of embodiments of the invention, the already cured hydrophilic foam is a first foam layer according to the invention, the second foam layer being produced from the aqueous mixture. Therefore, a foam layer with less retention capacity, which is the first foam layer according to the first aspect of the invention, is applied to the curing aqueous mixture of the second foam layer (step (iii). In). This specific order implementation contrasts with applying a prefabricated second foam layer with high retention capacity on top of the curing aqueous mixture of the first foam layer with less retention capacity. It is advantageous because the absorption of the aqueous mixture into the first foam layer and the associated increase in the thickness of the interface volume can be minimized.

In a plurality of embodiments of the invention, the method described above is from the first side of the first foam layer, across the interface between the first foam layer and the second foam layer, and. Further may include the step of providing a plurality of channels extending into at least a portion of the second foam layer. For example, multiple channels can be formed by punching (eg, using a rotating die cutting or needle), heating pins, and / or laser beam application.

The features and effects of this fourth aspect of the invention are largely similar to those described above in connection with the first, second and third aspects of the invention. The embodiments disclosed herein with respect to the first aspect, the second aspect and the third aspect apply with the necessary modifications to the fourth aspect.

According to a fifth aspect of the invention, the above and other objects are achieved by providing a medical dressing (particularly a wound dressing) comprising a composite material according to the invention.

In a plurality of embodiments of the invention, the medical dressing further comprises at least one additional layer, preferably a lining layer and / or an adhesive layer or coating, preferably two or more of these additional layers.

As will be apparent to those of skill in the art, the invention is by no means limited to the exemplary embodiments described herein. For example, medical dressings according to the invention include additional structural layers (s) that are fluidly communicated with the composite to further optimize the desired properties and / or achieve additional functionality. can do.

In a plurality of embodiments of the invention, the first hydrophilic polyurethane foam material as used in all embodiments of the invention described above comprises or is an isocyanate capping polyol or an isocyanate capping polyurethane. , The second hydrophilic polyurethane foam material obtained from the first prepolymer and / or as used in all embodiments of the invention described above, is isocyanate capping polyol or isocyanate capping polyurethane. Obtained from a second prepolymer that contains or is. In a plurality of embodiments of the present invention, the first prepolymer and the second prepolymer are different.

According to the present invention, the term "prepolymer" refers to A.I. D. McNaught and A.M. IUPAC: Compendium of Chemical Terminology, compiled by Wilkinson, 2nd Edition ("Gold Book"), Blackwell Scientific Publications, Oxford (1997), as defined in Oxford (1997), ISBN 0-9. Generally refers to a polymer or oligomer in which a molecule can enter further polymerization via a reactive group, thereby giving more than one structural unit to a chain of at least one type of final polymer. ..

In a plurality of embodiments of the present invention, the first prepolymer and / or the second prepolymer is a polyol and hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), or isophorone diisocyanate. Derived from the reaction with (IPDI), or a diisocyanate compound selected from the group consisting of any mixture thereof.

In a plurality of embodiments of the present invention, the polyol is a polyester polyol, a polyacrylate polyol, a polyurethane polyol, a polycarbonate polyol, a polyether polyol, a polyester polyacrylate polyol, a polyurethane polyacrylate polyol, a polyurethane polyester polyol, a polyurethane polyether polyol, a polyurethane polycarbonate. Polyesters and Polyesters Polyesters Polyesters Polyesters are selected from the group consisting of dicarboxylic acids or optionally tricarboxylic acids and tetracarboxylic acids or hydroxycarboxylic acids or lactones, in particular in addition to diols or optionally polycondensates of triols and tetraols.

Exemplary suitable diols are ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycol (polyethylene glycol, etc.), and further 1,2-propanediol, 1,3-propanediol, 1,3-butane. Diol, 1,4-butanediol, 1,6-hexanediol and isomers, neopentyl glycol or neopentyl glycol hydroxypivalate. In addition, polyols (such as trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl isocyanurate) are also within the scope of the present invention.

In a plurality of embodiments of the invention, the first prepolymer and / or the second prepolymer is derived from the reaction between the polyol and the aliphatic diisocyanate compound. For example, in a plurality of embodiments of the present invention, the diisocyanate compound is or comprises hexamethylene diisocyanate (HDI). Thus, in a plurality of embodiments of the invention, the first prepolymer and / or prepolymer is or comprises a hexamethylene isocyanate capping polyol or a hexamethylene isocyanate capping polyurethane.

In a plurality of embodiments of the invention, the first prepolymer and / or the second prepolymer is or comprises hexamethylene isocyanate capped polyethylene glycol.

In a plurality of embodiments of the invention, the first prepolymer and / or the second prepolymer is derived from the reaction between the polyol and the aromatic diisocyanate compound. For example, in a plurality of embodiments of the present invention, the diisocyanate compound is or comprises toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI). Therefore, in a plurality of embodiments of the present invention, the first prepolymer and / or the second prepolymer is a toluene isocyanate capping polyol or a methylene diphenyl isocyanate capping polyol, or a toluene isocyanate capping polyurethane or a methylene diphenyl isocyanate capping polyurethane. Or include them.

In a plurality of embodiments of the invention, the first prepolymer and / or the second prepolymer is or comprises toluene diisocyanate capping polyethylene glycol. In a plurality of embodiments of the present invention, the first prepolymer and / or the second prepolymer is or comprises methylene diphenyl isocyanate capped polyethylene glycol.

In a plurality of embodiments of the invention, the first hydrophilic foam material is obtained from a first prepolymer derived from a reaction between a first polyol and a first diisocyanate compound and is second hydrophilic. The foam material is obtained from a second prepolymer derived from the reaction between the second polyol and the second diisocyanate compound. In a plurality of embodiments of the present invention, the first diisocyanate compound and the second diisocyanate compound are the same, hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), or isophorone diisocyanate (IPDI). ) Etc.. In a plurality of embodiments of the present invention, the first diisocyanate compound and the second diisocyanate compound are different, for example, the first diisocyante compound can be toluene diisocyanate (TDI) and the second diisocyanate compound is hexamethylene. It can be diisocyanate (HDI). In a plurality of embodiments of the present invention, the first polyol and the second polyol can be the same, for example, the first polyol and the second polyol can be polyethylene glycol (polyethylene oxide). In a plurality of embodiments of the present invention, the first polyol and the second polyol are different. In a plurality of embodiments of the invention in which the first prepolymer and the second prepolymer are different, the first prepolymer may be toluene isocyanate capped polyethylene glycol and the second prepolymer may be hexamethylene isocyanate capped polyethylene glycol or. It can be methylene diphenyl isocyanate capping polyethylene glycol.

In a plurality of embodiments of the invention, the first foam layer and / or the second foam layer comprises an antimicrobial agent. In a plurality of embodiments of the invention, the antimicrobial agent comprises silver. In a plurality of embodiments of the present invention, silver is metallic silver. In a plurality of embodiments of the present invention, silver is a silver salt. In a plurality of embodiments of the present invention, the silver salt is silver sulfate, silver chloride, silver nitrate, silver sulfaziazine, silver carbonate, silver phosphate, silver lactate, silver bromide, silver acetate, silver citrate, silver CMC, silver oxide. Is. In a plurality of embodiments of the present invention, the silver salt is silver sulfate. In a plurality of embodiments of the invention, the antimicrobial agent comprises a monoguanide or a biguanide. In a plurality of embodiments of the present invention, the monoguanide or biguanide is chlorhexidine digluconate, chlorhexidine diacetate, chlorhexidine dihydrochloride, polyhexamethylene biguanide (PHMB) or a salt thereof, or polyhexamethylene monoguanide (PHMG) or a salt thereof. Is. In a plurality of embodiments of the present invention, the biguanide is PHMB or a salt thereof. In a plurality of embodiments of the invention, the antimicrobial agent comprises a quaternary ammonium compound. In a plurality of embodiments of the present invention, the quaternary ammonium compound is cetylpyridinium chloride, benzethonium chloride or poly-DADMAC. In a plurality of embodiments of the invention, the antimicrobial agent comprises triclosan, sodium hypochlorite, copper, hydrogen peroxide, xylitol or honey.

These and other aspects of the invention will be shown in more detail herein with reference to the figures illustrating exemplary embodiments of the invention.

It is a cross-sectional view of the embodiment of the composite material according to this invention. FIG. 5 is a cross-sectional view of an embodiment of a medical dressing according to a fifth aspect of the present invention. FIG. 5 is a cross-sectional view of an embodiment of a medical dressing according to a fifth aspect of the present invention. FIG. 5 is a cross-sectional view of an embodiment of a medical dressing according to a fifth aspect of the present invention. FIG. 5 is a cross-sectional view of an embodiment of a medical dressing according to a fifth aspect of the present invention. FIG. 5 is a cross-sectional view of an embodiment of a medical dressing according to a fifth aspect of the present invention. It is a schematic depiction of an embodiment of a composite material according to a second aspect of the invention.

In the following, detailed embodiments of the present invention will be described with reference to the accompanying figures, which are exemplary illustrations of the embodiments of the present invention.

FIG. 1 illustrates an embodiment of the composite material 1 according to the present invention. The composite material 1 includes a first foam layer 2 containing a first hydrophilic foam material of the hydrophilic polyurethane foam material 7 and a second foam layer 3 containing a second hydrophilic foam material 8.

As illustrated in FIG. 1, the interfacial bonded volume 4 exists between the first foam layer 2 and the second foam layer 3 and is general to all embodiments disclosed herein. The interface-bonded volume 4 does not contain any material other than the materials constituting the first foam layer 2 and the second foam layer 3, respectively.

The first foam layer 2 and the second foam layer 3 are directly bonded to each other at the interfacial coupling volume 4, eg, by means of physical interaction, thereby with additional bonding means (eg, foam layers 2 and 3). Avoid the need for an additional adhesive layer in between). This means that such an additional adhesive layer reduces the water vapor transmission rate (MVTR) through the composite material 1 and in fact a fluid in one of the foam layers (eg the composite material as a medical dressing or in it). If used in, it is advantageous as it can trap wound exudate). For example, if the composite material 1 was used as or in a medical dressing and the first foam layer 2 was adapted to contact and / or face the wound, it was absorbed by the first foam layer 2. Any exudate can migrate to the second foam layer 3 without having to pass through an additional adhesive layer.

In a plurality of embodiments of the present invention, the thickness d of the interface-bonded volume 4 is less than 200 μm, preferably less than 100 μm, and more preferably less than 50 μm. For example, in a plurality of embodiments of the present invention, the thickness d of the interface-bonded volume 4 is in the range of 10 to 200 μm (50 to 200 μm or 50 to 150 μm or 50 to 100 μm, etc.). In a plurality of embodiments of the present invention, the thickness d of the interface-bonded volume 4 is in the range of 10 to 100 μm (10 to 60 μm, etc.). The absorbency and / or retention capacity of the material is impaired in the interfacial bond volume 4, and the small thickness d of the interfacial bond volume 4 facilitates fluid transfer between the foam layers 2 and 3, so the interfacial bond volume 4 The minimum thickness d of is advantageous.

The composite foam material 1 according to an embodiment of the present invention allows two hydrophilic foam layers to be (more) strongly bonded together. Fluid transfer from one layer to another, as there is no adhesive or other material at the interface between the two layers, which may differ from the material (s) that make up the two layers. Is optimized. Along with the possibility of coordinating different functionality in the two layers, this makes it possible to optimize absorption and retention, among other things, in one overall foam material. This also provides a multi-layered (especially two-layered) foam complex, which has an active ingredient (eg, an antimicrobial agent) in only one layer, thus also making it possible to save costs.

For example, composite foam 1 is provided in a plurality of embodiments of the invention, the wound contact layer (eg, first foam layer 2) is optimized for rapid absorption and subsequent layers (eg, second foam layer 3). ) Can be optimized to have high fluid retention capacity. Similarly, the invention is capable of incorporating active substances (such as antimicrobial compounds) into the wound contact layer while still retaining foam with good absorption and good overall foam retention otherwise. To.

FIGS. 2a-2e illustrate exemplary embodiments of medical dressings 40, 50, 60, 80, 90 comprising composite material 1, such as realized in the form of layer order according to the present invention. Therefore, the medical dressings 40, 50, 60, 80, 90 shown in FIGS. 2a-2e are the first foam layer 2 and the second hydrophilic polyurethane foam material including the first hydrophilic polyurethane foam material 7. Includes a second foam layer 3 containing 8.

In a plurality of embodiments of the present invention, as shown in FIGS. 2a-2e, the medical dressings 40, 50, 60, 80, 90 have a lining layer 21 that overlays the upper side 31 of the second foam layer 3. And 23 are further included, and the upper side 31 is the side opposite to the side that binds to the first foam layer 2. Thereby, the first foam layer 2 has a wound facing side 35 that can function as a direct or indirect wound contact layer to absorb and retain wound exudate and / or. Transport the wound exudate from the wound to the upper second foam layer 3. In this configuration where the first foam layer 2 faces the wound, the first foam layer 2 may be advantageously adapted to provide rapid absorption of wound exudate. For example, in a plurality of embodiments of the present invention, the first foam layer 2 has an absorption rate of 10 μL / sec or higher, preferably 30 μL / sec or higher.

In a plurality of embodiments of the present invention, as shown in FIGS. 2a-b, the lining layer 21 extends outward of the periphery of the layer of composite material 1 and thus surrounds the periphery of the layer of composite material 1. The boundary portion 10 of the layer is defined, thereby providing so-called island dressing.

Suitable lining layers 21 and 23 are, for example, films, foils, foams or films. Further, the backing layer has a thickness in the region of 5 μm to 80 μm, particularly preferably 5 μm to 60 μm, and particularly preferably 10 μm to 30 μm, and / or the backing layer has an elongation at break of more than 450%. If you have, it is advantageous.

The lining layers 21 and 23 can be implemented to allow water vapor to pass according to DIN 53333 or DIN 54101.

Preferably, the lining layers 21, 23 may include or consist of thermoplastic polymers (eg, as a coating). Thermoplastic polymers are initially understood as polymers that remain thermoplastic if they are repeatedly heated and cooled within typical temperatures for their respective processing or application conditions. Thermoplasticity is a characteristic of polymer materials that repeatedly soften upon application of heating and repeatedly solidify when cooled, within the typical temperature range for each material. It is understood that, on a softened stage, and repeatedly, it remains formable by flow (eg, as a feature), extrusion, or other method.

Preferred thermoplastic polymers are polyurethanes, polyethylenes, polypropylenes, polyvinyl chlorides, polystyrenes, polyethers, polyesters, polyamides, polycarbonates, polyether polyamide copolymers, polyacrylates, polymethacrylates, and / or polymers. Preferably, the thermoplastic polymer is elastomeric. It is particularly preferred that the carrier foil contains or consists of a thermoplastic polyurethane resin (TPU). Thermoplastic polyurethane resins selected from the group comprising aliphatic polyester polyurethanes, aromatic polyester polyurethanes, aliphatic polyether polyurethanes, and / or aromatic polyether polyurethanes are particularly suitable. By using these polymers, it is possible to obtain a backing layer as a breathable elastic film. They are characterized by high flexibility and elasticity over a wide range of temperatures, and also have the property of favorably sealing water (liquid), while having high water vapor permeability. These materials are further characterized by low noise, a favorable textile feel, resistance to cleaning and cleaning, very good chemical and mechanical resistance, and the fact that they are plasticizer-free.

A lining layer, which acts as a barrier against pathogens and has a high sealing ability against exudate from the wound, while at the same time being permeable to water vapor, is also particularly preferred. To achieve this, the lining layer can be realized, for example, as a semipermeable membrane.

In a plurality of embodiments of the present invention, the lining layers 21 and 23 are preferably vapor permeable. The lining layers 21 and 23 may be, for example, polyurethane, polyethylene or a plastic film comprising or consisting of polypropylene. In a plurality of embodiments of the present invention, the backing layers 21 and 23 are polyurethane films having a thickness in the range of 10 to 100 μm, for example, 10 to 80 μm (10 to 50 μm, etc.), preferably 10 μm to 30 μm.

As schematically illustrated in FIGS. 2a-2e, medical dressings 40, 50, 60, 80, 90 include an adhesive layer or coatings 41, 42, 43 to the wound and / or surrounding skin surface. Medical dressings can be adhered. In a plurality of embodiments of the invention, the wound facing adhesive layer or coating 41, 42, 43 can be a silicone-based adhesive or acrylic-based adhesive, preferably the adhesive layer or coating is silicone-based. It is an adhesive. The term "coating" according to the present invention should be understood as essentially one continuous layer on the surface or a discontinuous cover on the surface.

The medical dressings 40, 50, 60, 80, 90 may further comprise a release layer (not shown) that is releasably connected to the adhesive layer or coatings 41, 42, 43 and can be removed prior to application. A suitable release layer comprises or consists of a material having limited adhesion to it, if made contact with the pressure-sensitive adhesive of the pressure-sensitive adhesive layer. An example of such a release layer is a release paper containing a non-adhesive silicone or polyolefin layer.

As shown in FIGS. 2b and 2d, the medical dressings 50, 90 include a perforated layer 44, made from, for example, a polyurethane film, and the adhesive coating 42 is provided on the non-perforated portion of the perforated layer 44. Will be done. The perforated layer 44 includes a plurality of openings 45 (or through holes) of any desired size and shape. The shape and size of the opening 45 may be adapted to achieve the desired fluid transport from the wound to the upper layer of composite material 1.

In a plurality of embodiments of the invention, as illustrated in FIG. 2b, the perforated layer 44 with the adhesive coating 42 may be provided on the wound-facing surface 35 of the first foam layer 2. The perforated layer 44 extends outward from the peripheral portions of the foam layers 2 and 3 of the composite material 1 and is attached to the boundary portion 10 of the lining layer 21.

In an alternative embodiment, as shown in FIG. 2d, the footprint of the perforated layer 44 corresponds to the footprint of the composite material 1. In a plurality of embodiments of the invention, as shown in FIG. 2c, the adhesive coating 43 is provided directly on the wound-facing surface 35 of the first foam layer 2. In a plurality of embodiments of the invention, as shown in FIG. 2a, the adhesive coating 41 is provided on a continuous plastic film 46 (eg, a polyurethane film as discussed above) and is continuous thereof. The plastic film 46 is arranged adjacent to the peripheral portion of the layer of the composite material 1, and the continuous film 46 extends away from the peripheral portion and is attached to the boundary portion 10 of the backing layer 21. In a further embodiment (not shown), the adhesive coating can be provided directly on the wound-facing surface of the border portion 10 of the lining layer 21.

In a plurality of embodiments of the invention, the medical dressing 60 as shown in FIG. 2e includes a central portion 12 beneath the composite material 1 and a boundary portion 11 extending outward from the peripheral portion of the composite material 1. The perforation 45 is present only in the central portion 12 and the perforated layer 46 is provided by the adhesive coating 41 so that the perforated layer 46 is included and the fluid can be transferred through the perforation 45 and into the composite material 1. Coated as above. The adhesive coating on the (non-perforated) boundary portion 11 of the perforated layer 46 is more adherent compared to the medical dressing 50 (perforations are also present in the boundary portion) shown in FIG. 2b. Provided is a medical dressing 60 having the ability (due to a larger sticky contact area).

FIG. 3 is a perspective view of an exemplary embodiment of the composite material 70, in particular according to a second aspect of the invention, wherein the composite material 70 is a first foam layer 2 comprising a first hydrophilic polyurethane foam material 7. including. The first foam layer 2 has a first side 35 adapted to face the area of application, preferably adapted to face the wound area during use. The composite material further comprises a second foam layer 3 containing a second hydrophilic polyurethane foam material 8. The second foam layer 3 is bonded to the second side of the first foam layer 2, the second side is opposite to the first side 35, and the interfacial coupling volume 4 is the first foam layer 2. It exists between the second foam layer 3 and the second foam layer 3. The plurality of channels 71 extend from the first side 35 of the first foam layer 2 through the whole and into at least a part of the second foam layer 3.

The channel 71 may typically have an average diameter (D) of 0.1 mm to 4.0 mm, preferably 0.5 mm to 3.0 mm, more preferably 1.5 mm to 2.5 mm.

As schematically illustrated in FIG. 3, the plurality of channels 71 are from the first side 35 of the first foam layer 2, through the thickness of the first foam layer 2, and the first. Across the interface volume 4 between the foam layer 2 and the second foam layer 3, the liquid transport into the core of the second foam layer 3 is promoted. As shown in FIG. 3, the plurality of channels 71 extend in the vertical direction (ie, in the z direction or in the direction of thickness perpendicular to the plane of layer 2).

The present inventor provides a plurality of channels 71 extending across the interface volume 4 and into the adjacent second foam layer 3 via the first foam layer 2, thereby providing a first foam layer. It has been found that fluid transport into and further through and subsequently into the second foam layer 3 can be improved. Thereby, the full absorption capacity of the composite material can be further optimized.

In particular, fluid transport across the interface (eg, interface volume 4) between the first foam layer 2 and the second foam layer 3 is further through at least a portion of the second foam layer 3 and further in the foam layer 2. It can be improved by a plurality of channels 71 that also extend through the interface between and 3.

In a plurality of embodiments of the present invention, the plurality of channels 71 extend at least a distance into the second foam layer 3, the distance being at least 5% of the total thickness of the second foam layer, preferably 5% or more. It corresponds to 15% or more, more preferably 25% or more.

The present invention is further illustrated in the following examples.

Method for Preparing First Foam Layer The first foam layer (for subsequent use in the preparation of the composite material) was prepared using the following steps (1-3). 1) An aqueous mixture was prepared (see Table 1 for chemicals and concentrations). 2) The aqueous mixture was mixed with the selected prepolymer (see Table 1) in a specified ratio by weight (see Table 1) to give an emulsion mixture. 3) The emulsion mixture was poured onto casting paper (20 x 30 cm), spread on paper and cured under standard conditions (at room temperature) to give a foam thickness of about 3 mm (thickness of the spread of the emulsion mixture in step 3). Control the foam thickness by adapting). As illustrated below, the chemicals used are available commercially. Baymedix® FP-505 (HDI-based prepolymer composition) is commercially available from Covestro and Trepol® B1 (TDI-based prepolymer) is available from Rynel Inc. Available as a commercial product from Air Products and Chemicals Inc., Polycat 77 is available from Air Products and Chemicals Inc. Available commercially from, Pluronic® L62, sodium bicarbonate and citric acid are all commercially available from Sigma-Aldrich, Fisher Scientific, and / or BASF.

Methods for Preparing Composites Composites according to embodiments of the invention were prepared under standard laboratory conditions (at room temperature unless otherwise stated) by the following sequence of steps (1-6). 1) An aqueous mixture was prepared (see Table 2). 2) The aqueous mixture was mixed with the selected prepolymer (see Table 2) in a specified ratio by weight (see Table 2) to give an emulsion mixture. 3) The emulsion mixture was poured onto casting paper (20 x 30 cm) and spread on paper. 4) A single foam layer (one of foam A, foam B or foam C) (20 x 30 cm) was applied to the top of the emulsion. 5) The emulsion mixture was cured under standard conditions (at room temperature) to give a foam thickness of about 3 mm (the foam thickness is controlled by adapting the spread thickness of the emulsion mixture in step 3). 6) The resulting complex product was dried in an oven at 40 ° C. per side for 10 minutes.

Steps 1 to 4 are performed in rapid, continuous steps, steps 1 to 4 are preferably completed in less than 4 minutes, thereby the desired degree of cure in the emulsion mixture when step 4 is initiated. (Typically 50-90%, preferably 70-80%) should be ensured. Specimens were prepared by die-cutting the dried complex product approximately to a size of 10 x 10 cm.

Unless otherwise specified, all percentage indications are intended to refer to weight percent. Curability was measured by Fourier Transform Infrared Spectroscopy (FTIR). Viscosity was determined at 23 ° C. and according to DIN 53019.

Methods and Results of Measuring Interfacial Bonded Volume Thickness Interfacial Bonded Volume Thickness (or Penetration Depth) is measured using a stereomicroscope equipped with a micrometer scale, i.e., between two foam layers. Interface volume was identified using a microscope and thickness (corresponding to the depth of interface volume in the direction of layer / composite thickness) was measured using a micrometer scale. It was determined that the thickness of the interfacial bonded volumes in the composites A, B and C measured accordingly were all in the range of 20-50 μm.

Due to the relatively low water content in the emulsion, as the urethane foam cures, essentially all or most of the water is contained within the bubble wall as a solvent / plasticizer, thus forming two foam layers. It cannot move freely into the previously prepared foam layer when bound together. Therefore, the thickness of the interfacial bond volume between the two foams is relatively small (especially less than 200 μm).

Determination of Free Swelling Absorption (Fluid Absorption) Capacity The free swelling absorption (or maximum absorption) capacity was determined according to EN13726-1: 2002 with the following minor modifications. Using a test piece with a size of 10 x 10 cm (thickness about 3 mm), the free swelling absorption capacity per volume unit of the test piece was calculated (ie, the mass of retained solution A per volume (m ³ ) (kg). )). When comparing hydrophilic foams with different densities, the weight per volume provides a more reasonable measurement (eg compared to the weight ratio as suggested in EN13726-1: 2002). The weight value per volume can be easily converted to the weight per weight by dividing the weight value per volume by the respective density values of the sample. The values of free swelling absorption capacity of foam layers A, B and C are presented below in Table 3.

Determination of fluid retention capacity According to the present invention, the fluid retention capacity is determined by first measuring the free swelling absorption (or maximum absorption) capacity according to EN13726-1: 2002. Subsequently, a rigid template (approximately the same size as the sample (10 × 10 cm) with a mass equivalent to 40 mmHg) is transferred to the sample (where it is immersed in solution A according to EN13726-1: 2002). Apply. After 2 minutes, the stiffness template is removed, the sample weight is measured again and the amount of residual water (retained solution A) is calculated. The fluid retention capacity is calculated by dividing the amount of retained solution A (kg) by the volume of the sample (m ³ ). The retention values for foam layers A, B and C are presented below in Table 3.

As shown in Table 3, both Foam A and Foam C have a higher fluid retention capacity than Foam B, for example Foam A has a 263% higher retention capacity compared to Foam B and is therefore composite. It can suitably function as a fluid holding layer in the material. In particular, foam B has a higher absorption rate than foam A and foam C, so that foam B can suitably function as a wound fluid trapping layer.

In a plurality of embodiments of the present invention, the first foam layer may be implemented by foam layer B and the second foam layer may be implemented by foam layer A or foam layer C.

Determination of Absorption Rate According to the present invention, the absorption rate is determined according to the TAPPI standard T558 OM-97, the method of which is surface absorption, among other things, as the volume of liquid remaining on top of the sample surface, measured as a function of time. To evaluate the properties, the test solution used herein is solution A from EN13726-1, and the volume of the droplets is 30 μl. The absorption rate of foam B in composites A, B and C (ie, the test solution was added to each foam B of composites A, B and C) was measured to be about 30 μl / sec. The absorption rates of Foam A and Foam C were about 3 μl / sec and about 10 μl / sec, respectively.

1 Composite material 2 First foam layer 3 Second foam layer 4 Interfacial bond volume 7 First hydrophilic polyurethane foam material 8 Second hydrophilic polyurethane foam material

Claims (17)

A first foam layer, comprising a first hydrophilic polyurethane foam material,
A second foam layer, comprising a second hydrophilic polyurethane foam material,
Is a composite material containing
The fluid holding capacity of the second foam layer is 20% or more larger than the fluid holding capacity of the first foam layer.
The fluid retention capacity is defined as the ability to initially absorb the maximum amount of solution A and retain solution A when exposed to a pressure of 40 mmHg for 2 minutes according to EN 13726-1: 2002.
An interfacial bond volume is present between the first foam layer and the second foam layer.
The interfacial bond volume comprises a mixture of the first foam layer and the materials constituting the second foam layer.
The thickness of the interfacial bond volume is less than 200 μm.
A composite material in which the thickness of the first foam layer is less than 40% of the total thickness of the composite material. The composite material according to claim 1, wherein the thickness of the interfacial bond volume is less than 100 μm. The composite material according to claim 2, wherein the interface-bonded volume has a thickness of 50 μm or less. The first foam layer comprising the first hydrophilic polyurethane foam material, the first foam layer having a first side adapted to face the application area in use.
With the second foam layer, which comprises the second hydrophilic polyurethane foam material,
Including
A plurality of channels extend from the first side of the first foam layer through the entire first foam layer into at least a part of the second foam layer, and the channels are 0. The composite material according to claim 1 , which has an average diameter of 1 mm to 4.0 mm. The composite material of claim 4 , wherein the first foam layer has a first side adapted to face the wound area. 1 . Composite material. The composite material according to any one of claims 1 to 6 , wherein the second foam layer has a fluid holding capacity of 800 kg / m ³ or more. Claimed that the first foam layer has an absorption rate of 10 μL / sec or higher when measured according to TAPPI standard T558 OM-97 using 30 μL of solution A according to EN1372-1: 2002 as the test solution. Item 5. The composite material according to any one of Items 1 to 7 . Whether at least one of the first foam layer and / or the second foam layer is obtained by a process containing less than 40% water in an aqueous mixture containing a prepolymer (leading to a hydrophilic urethane foam layer). Alternatively, the composite material according to any one of claims 1 to 8 obtained. The first hydrophilic polyurethane foam material is obtained from or obtained from a first prepolymer comprising or being an isocyanate capping polyol or isocyanate capping polyurethane, and / or the second hydrophilic polyurethane. The composite material according to any one of claims 1 to 9 , wherein the foam material contains or is obtained from a second prepolymer comprising or is isocyanate capping polyol or isocyanate capping polyurethane. The composite material according to claim 10 , wherein the first prepolymer and the second prepolymer are different. The polyols constituting the isocyanate capping polyol are polyester polyol, polyacrylate polyol, polyurethane polyol, polycarbonate polyol, polyether polyol, polyester polyacrylate polyol, polyurethane polyacrylate polyol, polyurethane polyester polyol, polyurethane polyether polyol, polyurethane polycarbonate polyol and Select from the group consisting of a polycondensate of at least one monomer selected from the group consisting of polyester polycarbonate polyol and diol, triol, tetraol, dicarboxylic acid, tricarboxylic acid, tetracarboxylic acid, hydroxycarboxylic acid, and lactone. The composite material according to claim 10 or 11 , which is at least one kind . The first prepolymer and / or the second prepolymer is a polyol and hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), methylene diphenyldiisocyanate (MDI), or isophorone diisocyanate (IPDI), or any of them. The composite material according to any one of claims 10 to 12 , which is derived from a reaction with a diisocyanate compound selected from the group consisting of a mixture. The composite material according to any one of claims 1 to 13 is included.
A medical dressing having a first side to which the first foam layer is adapted to face the application area during use . 14. The medical dressing of claim 14 , wherein the medical dressing further comprises at least one lining layer and / or an adhesive layer or coating. (I) A step of preparing an aqueous mixture containing a polyurethane prepolymer, wherein the water content of the aqueous mixture is less than 40% w / w relative to the total weight of the aqueous mixture.
(Ii) The step of applying the aqueous mixture from step (i) onto the carrier material, and
(Iii) An already cured hydrophilic polyurethane foam layer is cast onto the carrier material in step (ii) on top of the aqueous mixture before the aqueous mixture is essentially completely cured. Steps to apply and
(Iv) Allows the aqueous mixture to be cured substantially completely, thereby comprising a first foam layer comprising a first hydrophilic polyurethane foam material and a second comprising a second hydrophilic polyurethane foam material. And the steps to produce a composite material containing a foam layer of
A method of producing a composite material, including. 16. The method of claim 16 , wherein the degree of cure of the aqueous mixture is between 50 and 90% at the stage of applying the already cured hydrophilic polyurethane foam layer in step (iii).

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